Matala Heavy Duty Air Manifolds are built tough. Heavy brass construction for dependable use. The HD manifolds are available in 2 way or 4 way. The inlet barb which connects to the air pump is a 3/4" barb and will fit into the white L tube that comes with your Hakko air pump. The outlet barbs are available in 3/8", 1/2" or 5/8".